A combination of immunological and biochemical methods will be used to identifiy and isolate integral surface membrane components involved in adhesion. A broad spectrum antibody against hamster fibroblast membranes reversibly and nontoxically rounds and detaches hamster cells from the substratum in vitro. Using an antiserum neutralization assay (blocking assay) to detect components of interest a fraction containing a restricted population of glycoproteins has been identified. Further information is needed, however, in order to determine if one, a combination, or all of the glycoproteins play some role in cell substratum adhesion. To help answer this question we plan to use an adherent melanoma cell line, CS 473, and a nonadherent varient of this line, RPMI 3460, which can be induced to adhere to the substratum. Initial results demonstrate that the nonionic detergent extract of RPMI 3460 cells expresses 10-fold less blocking activity than does a similar extract from CS 473 cells, and that the antigen of interest is expressed on RPMI 3460 cells when they are induced to adhere to the substratum. This dynamic system should permit us to identify and isolate an integral cell surface membrane, involved in cell-substratum. Purified antigen will then be used to raise polyclonal, monospecific and monoclonal antibodies to be used in cellular localization and quantitation of the antigen on various cells both in vitro and in vivo. The information gained from these studies should increase our understanding of how the integral and peripheral cell surface components are organized in a cell capable of adhesion and how this differs in a nonadherent cell.